LED front lighting arrangement

Abstract

A lighting arrangement for use in automotive front lighting and a method of producing such an arrangement are described. At least one LED lighting element 40 is provided for emitting light. A collimator 10 is provided for forming an emission pattern of the emitted light, which is subsequently projected by a secondary optic arrangement 42 . The collimator 10 comprises a cutoff reflector surface 18 with a front edge 30 and a back edge 32 . The back edge 32 is located adjacent to the LED lighting element 40 . The front edge is spaced from the back edge 32 in a depth direction X, A. The front edge 30 is arranged as a shielding edge for forming a light/dark cutoff in the emission pattern. First and second lateral reflector surfaces 26 a , 26 b are arranged opposite to each other adjacent to the LED lighting element 40 . The front edge 30 of the cutoff reflector surface 18 is arranged within a focal area of the secondary optic arrangement 42 . For providing a beam pattern well suited for automotive front lighting, the first and second lateral reflector surfaces 26 a , 26 b extend further into the depth direction A, X than the cutoff reflector surface 18.

The invention claimed is: 
     
       1. Lighting arrangement comprising:
 at least one LED lighting element having a primary optic arrangement for emitting light, 
 at least one collimator for forming an emission pattern of said emitted light, 
 and a secondary optic arrangement for projecting said emission pattern, 
 wherein said collimator comprises:
 a cutoff reflector surface with a front edge and a back edge, said back edge being located adjacent to said LED lighting element, and said front edge being spaced therefrom in a depth direction (X, A), said front edge being arranged as a shielding edge forming a light/dark cutoff in said emission pattern, 
 and first and second lateral reflector surfaces arranged opposite to each other adjacent to said LED lighting element which flare out from an area nearest the LED lighting element, 
 wherein said front edge of said cutoff reflector surface is arranged between the primary optic arrangement and the secondary optic arrangement at least substantially within a focal area of said secondary optic arrangement at a distance from the secondary optic arrangement that substantially corresponds to a focal distance of the secondary optic arrangement, 
 wherein said first and second lateral reflector surfaces extend further into said depth direction (X, A) than said cutoff reflector surface, and beyond the focal area of the secondary optic arrangement, such that the resulting emission pattern has no sharp light/dark cutoff in lateral direction, and 
 wherein said first and second lateral reflector surfaces have an S shape, with smooth transitions between angles, in cross-sectional view with at least a first angle portion that forms a first opening angle with a central geometrical axis (A) and a second angle portion that forms a second opening angle with the central geometrical axis (A), wherein said first angle portion is arranged closer to said LED lighting element than said second angle portion, and wherein said first opening angle is larger than said second opening angle. 
 
 
     
     
       2. Lighting arrangement according to  claim 1 , wherein said collimator further comprises a foreground reflector surface arranged opposite to said cutoff reflector surface, wherein said foreground reflector surface extends further into said depth direction (X, A) than said cutoff reflector surface. 
     
     
       3. Lighting arrangement according to  claim 2 , wherein said cutoff reflector surface, said foreground reflector surface and said lateral reflector surfaces each have back edges forming a window for said light emitted from said LED lighting element. 
     
     
       4. Lighting arrangement according to  claim 1 , wherein at least one of said first and second lateral reflector surfaces is arranged with an opening angle between said surface and a central geometrical axis (A), wherein said opening angle is measured from a back edge of said lateral reflector surface, which is arranged adjacent to said LED lighting element, and a front edge of said surface, which is arranged distant to said back edge in said depth direction (A), is 5°-45°. 
     
     
       5. Lighting arrangement according to  claim 1 , wherein a shape of said at first and second lateral reflector surfaces is continuous between said portions. 
     
     
       6. Lighting arrangement according to  claim 1 , wherein said front edge of said cutoff reflector surface has a shape corresponding to a curve running at varying distances from said LED lighting element in said depth direction (A, X). 
     
     
       7. Lighting arrangement according to  claim 1 , wherein said front edge of said cutoff reflector surface has a shape including two at least substantially straight portions and an angle portion arranged in between said straight portions. 
     
     
       8. Lighting arrangement according to  claim 1 , wherein said secondary optic arrangement comprises a lens. 
     
     
       9. Lighting arrangement according to  claim 1 , wherein at least one of said reflector surfaces of said collimator is a surface of a part made of plastic with a reflective coating provided on said surface. 
     
     
       10. Lighting arrangement according to  claim 9 , wherein said cutoff reflector surface and at least one of said lateral reflector surfaces are surfaces of at least one part made of plastic with a reflective coating, wherein the reflective coating provided on said cutoff reflector surface is different from a reflective coating provided on said lateral reflector surface. 
     
     
       11. Lighting arrangement according to  claim 1 , wherein said LED lighting element comprises a light emitting plane, wherein a length of said plane in a width direction is larger than a length of said plane in a height direction perpendicular thereto. 
     
     
       12. Lighting arrangement according to  claim 1 , wherein said first and second lateral reflector surfaces extend into said depth direction (X, A) by at least 50% further than said cutoff reflector surface. 
     
     
       13. Method for producing a lighting arrangement, comprising
 providing at least one LED lighting element having a primary optic arrangement for emitting light, 
 providing at least one collimator for forming an emission pattern of said emitted light, 
 providing a secondary optic arrangement for projecting said emission pattern, 
 wherein providing said collimator comprises:
 arranging a cutoff reflector surface with a front edge and a back edge, said back edge being located adjacent to said LED lighting element, and said front edge being spaced therefrom in a depth direction (A, X), said front edge being arranged as a shielding edge forming a light/dark cutoff in said emission pattern, 
 arranging first and second lateral reflector surfaces opposite to each other adjacent to said LED lighting element which flare out from an area nearest the LED lighting element, 
 arranging said front edge of said cutoff reflector surface between the primary optic arrangement and the secondary optic arrangement at least substantially within a focal area of said secondary optic arrangement at a distance from the secondary optic arrangement that substantially corresponds to a focal distance of the secondary optic arrangement, 
 arranging so that said first and second lateral reflector surfaces extend further into said direction (A. X) than said cutoff reflector surface, and beyond the focal area of the secondary optic arrangement, such that the resulting emission pattern has no sharp light/dark cutoff in lateral direction, and 
 arranging said first and second lateral reflector surfaces to have an S shape, with smooth transitions between angles, in cross-sectional view with at least a first angle portion that forms a first opening angle with a central geometrical axis (A) and a second angle portion that forms a second opening angle with the central geometrical axis (A), wherein said first angle portion is arranged closer to said LED lighting element than said second angle portion, and wherein said first opening angle is larger than said second opening angle. 
 
 
     
     
       14. Method according to  claim 13 , wherein at least a part of said collimator is made of plastic in an injection molding process, wherein a reflective coating is provided on a surface of said part to form one of said reflector surfaces.